Unvented water heaters are less space-consuming. These heaters are specially designed to take less area and fit in perfectly in modern homes. tradeplumbing.co.uk/central-heating/cylinders/vented-hot-water-cylinder/direct-hot-water-cylinders.html…Unvented water heaters are less space-consuming. These heaters are specially designed to take less area and fit in perfectly in modern homes. tradeplumbing.co.uk/central-heating/cylinders/vented-hot-water-cylinder/direct-hot-water-cylinders.htmlWW…